Elevator door operator



July 10, 1934. H. v. MCCORMICK ELEVATOR DOOR OPERATOR Filed June lO, 1932 INVENTOR WITNESSES: a

Nm ww Patented July 10, 1934 UNITED STATES ELEVATOR DOOR OPERATOR Harold V. McCormick, Winnetka, Ill., assigner to Westinghouse Electric Elevator Company, Chicago, Ill., a corporation of Illinois Application June 10, 1932, Serial No. 616,466

2 Claims.

My invention relates to elevator door operators and more particularly to such devices as are employed for operating center-opening elevator doors.

In elevators constructed with center-opening sliding doors, it is a common practice to drive one door by means of an operating member and to drive-the opposite door through an over-head motion-transmitting mechanism attached to the first door. Many diculties have been encountered in securing a suitable over-head operating mechanism for moving the two doors simultaneously in opposite directions.

in some installations the over-head operating mechanism has included a gear-pinion mounted above the doors at a point near the center of the doorway and a gear-rack attached to each door, one rack meshing with the top portion of the pinion and the other rack with the bottom portion of the pinion. This construction has proved to be very rugged, but it has also proved to be very noisy because of the vibration set up by the meshing of the gear teeth. Furthermore, the vibration caused by the meshing or the gear teeth not only produces a noise or itself, but also rat es any joint that is not tight on the doors or their hangers. It has been possible to reduce the noise from the loose joints by keeping a constant watch on them to keep them tight, but no way has been found to reduce the noise in the gear racks and pinion.

In other instances, use has been made of another form of over-head motion transmitting mechanism comprising a pair of sprockets and a chain. Usually the sprockets are placed one at each end of the hanger rail upon which the doors are mounted, and the chain is operated over them, one door being secured to the under portion of the chain and the other door being secured to the upper portion of the chain. The chain and sprocket mechanism is considerably more quiet than the rack and pinion construction in operation, but it is not as rugged. Inasmuch as the chain is substantially non-elastic it frequently fractures when the power-means for operating the doors is reversed. Furthermore, a chain has many pin connections, each or which wears slightly, and in time causes the chain to. become slightly slack, thereby causing the door operation to be poor and noisy, and increasing the probabiilty of fracture of the chain under a reversal load.

Therefore, it is an object of my invention to provide a door operating mechanism that is rugged in construction and which will remain practically noiseless in operation.

Another object of my invention is to provide a mechanism that may be readily and quickly adjusted to compensate for wear that may occur in its operating parts.

A further object of my invention is to provide a mechanism that will permit a limited amount of yielding movement between itself and the doors when the doors are suddenly reversed, thereby still further reducing the probability of breakage and the noise usually incident to the operation of center-opening doors.

It is also an object of my invention to provide a center-door operating mechanism that may be easily and cheaply constructed, installed and maintained in operation.

Other objects of my invention will become .evident from the following detailed description taken in conjunction with the accompanying drawing, in which:

Figure 1 is a View, in front elevation, of a door operating mechanism embodying my invention, as applied to a pair of slidable center-opening doors, only the upper portions of which are shown; p

Fig. 2 is a top plan view of the operating mechanism shown in Fig. 1;

Fig. 3 is an enlarged View taken on the line III-III of Fig. 1;

Fig. 4 is an enlarged View taken on the line IV-IV of Fig. 1;

Fig. 5 is an enlarged view taken on the line V-V of Fig. 1;

Fig. 6 is a View showing the construction of the cable embodied in the door operating mechanism; and,

Fig. 7 is a View taken on the line VIVI-VII of Fig. 6.

Referring more particularly to the drawing, the invention is illustrated as applied to a pair of center-opening doors 1 and 2 supported upon a track-rail 3 by means of a plurality of hangers 4 in such manner as to slide along the track-rail when they are opened or closed.

As shown in Fig. 3, each of the hangers 4 comprises a frame plate 5 that is secured to the upper part of the door supports by means of a plurality of bolts 6. The upper portion of the plate 5 is bent over and downwardly to provide a mounting for a pin 7 upon which a grooved track-wheel 8 is rotatably mounted. A pivot pin 9 mounted in the lower portion of the hanger plate 5 provides a support for a roller 10. The position of the grooved wheel 8 in the hanger enables it to ride along the top of the track-rail 3, upon which it is mounted, While the position of theroller 10 permits it to engageV the bottom portion of the track-rail and prevent the hanger from becoming dislodged or from binding in operation on the rail. From this construction of the hangers, it will be understood that the doors may be moved easily along the track-rail 3 in opening or closing the doorway, indicated by the door frame 11.

The track-rail 3 is supported upon the `door frame 11 by a plurality of brackets 13, secured kmultaneously with the door 1.

to the door frame by a plurality of bolts 14. It will be noted that the track-rail is mounted upon an o'lset portion of each of the brackets 13 by means of a rivet 15 in such manner that it provides an unobstructed path for the rollers 8 and 10, when the doors are opened or closed.

A pair of toggle levers 16 and 17 are provided for applying power to open and close the doors. One end of the lever 16 is pivotally mounted by a bolt 18 in a bracket 19 that may be secured to the door frame 11 in which the doors are mounted. The other end of-the lever 16 is pivotally connected by a bolt 20 tor one end of the lever 17, the other end of which is pivotally connected by a bolt 21 to the door 1. A depending lug 22 is attached to the lever 16 for attachment to a motor or other device (not shown) for operating the doors by power. For convenience, a handle 23 is secured to the front end of the lever 17 so'that the toggle levers may be moved manually-either to or from their straight-line position in operating the door.

A pin 25 is mounted on the lever 16 in a position to be engaged by a slotted portion of the lever` 17, for the purpose of maintaining the connecting pivotal centers of the toggle mechanism in alignment when the doors are closed.

It is desirable to have the door 2 operate si- To accomplish this purpose I have provided a new and improved Y motion transmitting mechanism including a pair of sheaves 27 and 28, and two portions 29 and 30 of a specially constructed cable.

The sheave 27 is pivotally mounted near the left-hand end of the track-rail 3 by means of a bolt 31 supported by a bracket 32 which issecured to the door frame 11 by a plurality of bolts 33. The sheave 28 is supported at the right-hand end of the track-rail 3 by a pin 34 and a bracket 35 similar to and supported in the same manner as the bracket 32.

The cable comprises, as shown in Figs. 6 and 7, a steel core 38, provided with a rubber coating 39. The steel core 38 may comprise any suitable number of strands and should be pre-stretched by operating it under partial loading condition for a suitable interval of time before the rubber coating is applied. After the cable has been prestretched, a coating of live rubber, such as is employed in automobile tires, is vulcanized upon the steel core and built up to a suitable size. 1' have found that a steel or metallic core of approximately 1/4 in. in diameter upon which a suitable covering of live rubber has been built, up to a 1/2 in. in diameter, provides a satisfactory cable.

The cable may be attached to the doors and passed around to the sheaves in any suitable manner. In the present instance, I have shown the cable 29 as having its steel core 38 attached to a connector 40, by suitable bolts 41, which connec- 'tor in turn is pivotally secured by a pin 42 to the hanger 4a attached 'to the door 1. A collar 43 surrounds the pin 42 and spaces the connector the correct distance apart from the hanger 4a.

The other end of the cable 29 passes around the sheave 27 and has its steel core secured to the vhanger 4b, mounted on the door 2.

-adjustably held in position in the bracket 46 by suitable nut-s 48. If the length ofthe cable portion 29 becomes too long or too short in service, its length may be adjusted by rotating the nuts 48 in the direction necessary to give the cable portion 29 its correct working length.

One end of the cable portion 30 is secured t0 l the hanger 4b by a suitable pivotal connection 50 and the other end passes around the sheave 28 and is fastened by pivotal connection 51 and an eye-bolt 52 to a bracket 53, secured to the hanger in a manner similar to that in which the cable portion 29 is fastened to the door hangers. It will be observed that the rubber coating 39 is skinned away from the ends of the cable and that the door hangers are so connected to the metallic core of the cable that the load tension in operating the doors is applied directly to the metallic core.

With the lower adjacent ends of the cable portions attached to the hanger 4a on the door 1, and the upper adjacent ends of the cable portions secured to the hanger 4b on the door 2, any movement of the door 1 by the toggle levers 16 and 17 will be transmitted to the door 2 through the cable portions ruiming around the sheaves 27 and 28 and thereby cause the door 2 to move in an opposite direction. For instance, if the toggle arms 16 and 17 are broken from their straightline position, the door 1 will be forced into its open position, thereby moving the section of the cable underneath thesheaves to the left. This movement of the cable will cause the portions of the cable above the sheaves to move to the right, and inasmuch as they are rmly attached to the hanger 4b on the door 2, the door 2 will be forced to the right simultaneously with the movement of the door 1 to the left.

Conversely, when the toggle levers 16 and 17 are moved to their straight-line position to close the door 1, the portions of the cable underneath the sheaves 27 and 28 will be moved to their right by reason of the fact that they are attached to the hanger 4a on the door 1, and this movement will cause the portions of the cable above the sheaves to travel to the left, and by reason of their attachment to the hanger 4b on the door 2, move the door 2 to its closed position simultaneously with the movement of the door 1 to its closed position.

Inasmuch as the doors are connected to the metallic cores of the cable, the core itself will take all the tension load and the live rubber coating will take all the abrasive wear where it passes around the sheaves. The fact that all of the tension load is on the metallic core and none of it is on the rubber coating permits a limited amount of relative movement between the sheaves and the core. This provision for relative movement effects a cushioning effect on the doors and operating means therefor, when the doors are suddenly reversed in operation, as sometimes occurs, thereby eliminating a certain amount of noise usually incidental to the reversal of the doors and also reducing the probability of breakage in the motion-transmitting mechanism when the doors arereversed.

Furthermore, the provision o1' the vulcanized coating of live rubber on the metallic core removes all abrasive wear from the metallic core, and thereby permits the use of a smaller wire than would otherwise be necessary. A still further beneficial effect of the rubber coating is that it permits the use of a cable having small enough diameter wires to operate without undue breaking from bending over sheaves which must of necessity be rather small in diameter in elevator door operation. In the present instance, I am able to employ sheaves as small as 4% diameter. The use of small sheaves also permits the use of a small compact mechanism that requires but little space above the doors to be operated thereby.

Therefore, it Will be seen that I have provided a center-door operating mechanism that is strong and rugged in construction, which is simple and easy to construct and operate, and Which is practically noiseless when irst installed and which remains very quiet in its operation during its lifetime.

Although I have illustrated and described only one specic embodiment of my invention, it is to be understood that many changes and modifications may be made therein without departing from the spirit and scope of the invention.

I claim as my invention:

l. In a mechanism for operating a pair of cem ter opening doors in a door frame, a plurality of s` eaves rotatably mounted on said frame, a flexib .e stranded metallic cable passing around said sheaves and supported thereby, means for connecting the lower portion of the cable to one door and the upper portion of the cable to the other door whereby movement of one door in one direction will effect a corresponding movement of the other door in an opposite direction, and a live rubber coating vulcanized on the portions of the metallic cable that pass around the sheaves, said rubber coating being sufficiently thick to increase the diameter of the coated portions of the cable to approximately twice the diameter of the me. tallic cable to permit a limited cushioning movement between the sheaves and the metallic cable, when the movement of the doors is suddenly reversed.

2. In a mechanism for operating a pair of center opening doors in a door frame, a pair of sheaves rotatably mounted on said frame, a prestretclied flexible stranded metallic cable passing around one of said sheaves, adjustable means for connecting one end of the cable to one of the doors and the other end of the cable to the other door, a second pre-stretched exible stranded metallic cable passing around the other of said sheaves, adjustable means for connecting one end of the second cable to one of said doors and the other end to the other door, whereby movement of one of the doors Will effect a correspending movement of the other door, and a thick live rubber coating vulcanized on each of the portions of the cables that pass around the sheaves, said rubber coating being suiciently thick to increase the diameter of the coated portions of the cables to approximately twice the diameter of the metallic cables to permit a limited cushioning movement between the sheaves and the metallic cable when the movement of the doors is stopped.

HAROLD V. MCCORMICK. 

